R/C Ground Effect Vehicle with LiDAR Altitude Control

so this is the story about how i arrived here with this lovely little ground effect vehicle that uses lidar to maintain altitude big thanks to simplisafe for sponsoring this video more on them later it all started about six years ago when i built a flying sled that just so happened to be pretty good at staying in the ground effect if you're not familiar with the concept the ground effect happens when an aircraft flies really low and a bubble of high pressure air gets trapped underneath kind of like a hovercraft but not it also causes the wingtip vortexes to get flattened and pushed out further which effectively lengthens the wingspan of the aircraft after the snow melted i tried to sled out on water but it was a bit harder to keep in the ground effect because water has more friction than snow it would take more throttle to get off the water but once it broke contact it would just take off like an airplane and not stay low this made it really difficult to stay at the perfect altitude just above the surface of the water but not actually touching the water for this reason it's difficult to keep small aircraft like this in the ground effect it's not as much of a problem for big aircraft because the dynamics of the system are totally different but for small aircraft it's definitely a challenge that got me thinking wouldn't it be nice to have a robot control the throttle for you that brings us to 2021 where we now have little tiny lidar rangefinder chips that just so happen to be supported by ardupilot usually these are used on drones for collision avoidance and more accurate landing control but thanks to sebastian here we were able to modify the arduplane code and utilize them for ultra precise altitude control while in the ground effect or at least that was my idea i started building a foam board model that sort of resembles the air fish 8 which is a full scale vehicle made by a company in singapore in order to more easily develop and tune the rangefinder altitude control system i designed it this test platform with wheels to operate on land instead of water here are some shots of the first test oh god damn it i probably should have ailerons on this so it can stabilize when stuff like that happens but there's no ailerons so it just flips and breaks it's a robot [Music] oh yeah whoa after that i added some ailerons and took it out to the field for some testing [Music] turns out the field was too bumpy saying it the wheels broke off and the wind got messed up so since it was basically trashed i taped it back together said yolo and threw it in the air like an airplane even though that's not what it's designed for amazing if i cut the throttle it just stalls instantly oh oh oh oh wow that's so funny the thrust line on the motor is just so bad on this plane if i give it too much thrust it just immediately nose dives and if i don't give it enough thrust it just stalls instantly [Music] near miss [Music] i just crashed into my car oh no oh right into my windshield too that's so bad the only thing keeping this plane in the air right now is the flight controller okay let's go to manual mode oh oh it's not even controllable not at all the pitch is way too unstable yeah ardu pilot flight stabilization is pretty damn impressive [Applause] it looks like it flies really well but trust me it doesn't i think this airframe ultimately had a few significant issues that prevented it from ever working well for one it was probably too tail heavy even though i had a relatively huge 3 amp hour 4s lipo all the way forward in the nose also the motor position was too high up above the center of gravity this would cause the nose to pitch down when the throttle is increased this is kind of the exact opposite of what we want since our control loop is trying to control altitude with throttle wow this thing is pretty messed up at this point so we're just gonna go try and do one last little ground effect vehicle flight on pavement before i take it apart thrust too too high back this is going poorly frustration in the parking lot but still daniel won't give up yeah it's just flaring i think it is tail heavy did i just hit that kid i'm sorry after that i decided to scrap the airfish model and try out a more traditional echrono plan design i threw together a quick foam board model and plopped in the same electronics once again i headed out to the field but this time my idea was to try and fly like an airplane first and use the auto-tune feature in ardupilot to get the pid control loop styled in it flew fairly well not as well as a normal plane should but certainly better than the air fish [Music] once the flight controller's control loops were behaving well we set up for the first ground effect tests now a word about the sponsor of this video simply safe my roommates have done a pretty good job at protecting our home from threats system is now activated but despite all this we still felt like it might be nice to have a little extra protection that's why we got simply safe simply safe brings home security into the digital age with a network of sensors that connect to your wi-fi this allows for full control and real-time monitoring all through your smartphone probably sounds pretty complicated huh turns out it's actually really easy they offer step-by-step instructions and installing the sensors is as easy as peeling the cover off the adhesive backing and sticking it to the wall they have a wide range of sensors that protect against almost every threat you can think of they're all super sleek and modern looking they even offer a professional monitoring service that will call the police if trouble is detected visit simplisafe.com rc test flight to check out simplisafe's award-winning home security that keeps your home safe around the clock it's really reliable easy to use and there are no contracts now back to the video it was at this point where sebastian and i were still trying to figure out the best way to implement the ground effect altitude control and this is what we came up with in rdpilot there are four custom parameters there's altitude min altitude max throttle min and throttle max these basically just define a slope that controls your throttle based on the readings from the lidar distance sensor the slope of the line can be thought of like the proportional gain in a pid control loop the steeper it is the more reactive the system gets our initial tests went really well but this was a bit deceiving because it was a very calm evening so the control system had fewer disturbances to fight against oh that's too good that's so good oh i love it sick oh it's so good so sick so after that we took the chrono plant out to do some filming with ross here who's a professional cinema fpv pilot and you're gonna follow me with that it's gonna be wild that's pretty sick let's see i wanna see how sick baby down come back i think we're gonna go after this car ready yeah okay let's do it chase that plane bands chase that plane rc test flight truck daddy ross has a drone and sebastian remix the chrono plan that's the plan foam board hot glue software by sebastian proximity proximity reduce the wing to vortices motors in the front elevators in the back manual adjustment on my angle of attack shooting light on try not to [Music] that guy said not to run over his drone [Music] it's a little bit more turbulent than i had hoped yeah so it's kind of all over the place it's pretty windy out there i mean for this light of a plane it's a bit yeah it's very light after that i decided to spend some more time trying to dial in that slope we were talking about earlier on a few of the outings it ended up being too windy which made it difficult [Music] oh that's working pretty well or not finally we got a calm evening and had the chance to try out a bunch of different settings we started with a really steep slope which basically correlates to a super high p term if you've ever tuned a drone you'll know that having your p term too high will cause oscillation and that's what we were seeing here after that we gradually reduced the angle of the slope until it started holding altitude fairly well these are the final parameters we arrived at oh yeah oh yeah it's certainly not perfect and any amount of breeze makes it bounce around quite a bit but for such a small lightweight aircraft it's not bad [Music] our throttle min setting was still above the glide slope of the hill so it just flew even though it was in ground effect mode now you might be thinking well what's all the fuss about big ground effect vehicles don't rely on advanced electronics to stabilize their altitude and that's true at a larger scale the ground effect is more noticeable and vehicles are much more docile and slower to react little vehicles like this one are much more squirrely which makes them harder to control i think there's opportunity for a lot of improvement here right now we're solely relying on throttle to control altitude and altitude is basically a byproduct of airspeed to control altitude with high fidelity we would need to be able to control the air speed with high fidelity and that's hard to do because you basically have to rapidly accelerate and decelerate the whole vehicle so in other words solely relying on throttle to control the altitude is a bit too sluggish for this to be super precise to get around to this we could try using the elevator to control altitude but that's actually a bit trickier than you might think and a good topic for a future video that's all for now thanks for watching bye

Channel: rctestflight

Views: 441,689

Rating: 4.9079065 out of 5

Keywords: ekranoplan, gev, ground effect, ground effect vehicle, WIG, wing in ground, RC, lidar, distance sensor, rangefinder

Id: nvMUYdr5_g8

Length: 13min 0sec (780 seconds)

Published: Fri Apr 23 2021

Reddit Comments

[u/Corvegas]

Several entertaining videos, thanks for the heads up.

[u/Etione49]

Yo this is really cool; not sure why the downvotes. Thanks for posting.